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Soyuz 7K-T No. 61

INSIDER CONTENT

Soyuz-14

The USSR launches dress rehearsal for a joint mission with Apollo

On Dec. 2, 1974, Soyuz-16 went into orbit with a crew of two to test critical hardware and operations for the upcoming docking with the Apollo spacecraft scheduled in the summer of 1975.

Soyuz-16 mission at a glance:

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Soyuz-16 flight program

Two unpiloted flights of the 7K-TM spacecraft, in April and August 1974, validated the latest upgrade of the Soyuz for piloted missions. At the time, at least four more 7K-TM vehicles (No. 73 to 76) were in the production pipeline.

In its final configuration, the third ship, with production number 11F615A12 No. 73, diferred from the two previous vehicles by a test ring mounted on its docking port, which was intended for mechanical tests of the new androgynous mechanism developed for the Apollo-Soyuz mission. Attached to the port with the main latches of the docking mechanism, the extra ring simulated the counterpart docking interface of the Apollo spacecraft. There were also eight fully armed pyrotechnic bolts for the back-up undocking method, also intended for testing during the flight. (201)

Vehicle No. 73 was outfitted to spend six days in orbit with two crew members, matching the flight duration of the Soyuz flight during the joint mission with the Apollo. All critical equipment and procedures planned for the docking mission were expected to be in place for the dress rehearsal, including the operation to reduce the atmospheric pressure from 760 millimeters of mercury table to 540 millimeters and an increase the oxygen content from 20 percent to 40 percent, in order to facilitate the future transfer into the oxygen atmosphere of the Apollo.

The only major difference from the Apollo-Soyuz launch profile was the timing of the launch. Because the rehearsal mission fell on the short days of December 1974, the flight planners faced limited time windows for a suitable reentry and landing orbit which would put the Descent Module in a desired landing site in early daylight hours for the safest recovery operations. As a result, the launch time of the rehearsal mission was set for 09:40 GMT, instead of 12:20 GMT for the Apollo-Soyuz mission which was planned in the middle of the summer with far more daylight in the Northern Hemisphere. (50)

Logically, trainees from a cosmonaut group that was being prepared for the joint Apollo-Soyuz mission, ASTP, became candidates for the first crew to fly the 7K-TM test mission. A total of four two-person crews were training for the ASTP project since May 1973:

• Aleksei Leonov and Valery Kubasov — the primary crew for the joint flight;
• Anatoly Filipchenko and Nikolai Rukavishnikov — the primary crew for the first rehearsal flight;
• Yuri Romanenko and Aleksandr Ivanchenkov — the primary crew for the second rehearsal flight;
• Vladimir Dzhanibekov and Boris Andreev — a back-up crew. (231)

Because the cosmonauts had to familiarize themselves with the American equipment, all the trainees, including rookery cosmonauts who would not ultimately fly, were disclosed to the general public at one point or another in a major break with the Soviet secrecy protocols which would normally classify the names of crew members until they had made it into orbit. The fact of the preparations for the dress rehearsal flight and its overall mission objectives were also revealed to NASA, unlike in the situation with the two previous unpiloted flights of the 7K-TM variant in April and August 1974, which the Soviet head of the Apollo-Soyuz project Konstantin Bushuev apparently first mentioned only after the fact, at the end of August and early September of that year in conversations with his US counterpart Glynn Lunney.

Among other things, the two sides apparently discussed an opportunity to test communications between newly installed US-built radios aboard Soyuz and NASA's mission control center in Houston. The Soviet specialists considered giving NASA a notification five days ahead of the upcoming dress rehearsal mission, which they then predicted for the end of 1974. The Soviets were also expected to share planned and post-launch orbital parameters for the flight, so that the Americans could practice tracking the Soyuz in orbit with their own assets and then compare their observations with those by the Soviet engineers. Obviously, that experience would be critical for the upcoming rendezvous mission.

However, the talks hit a stumbling block when the Soviet side asked for an embargo on public disclosure of these interactions until the USSR would itself announce the mission after its successful launch, which NASA found in conflict with its policies. On Oct. 11, 1974, Lunney sent a fax to Bushuev expressing his understanding of the situation but proposed to postpone all data exchanges until these activities could be made public. (1044)

Beyond these extraordinary contacts, the Vehicle No. 73 launch campaign was surrounded by the usual secrecy and since US officials familiar with the matter adhered to the Soviet rules, the launch of what would become Soyuz-16 came without any prior notice to the general public. (50)

Soyuz-16 lifts off

A Soyuz-U rocket carrying the Soyuz 7K-TM No. 73 spacecraft lifted off on Dec. 2, 1974, at 12:40:00 Moscow Time from Site 1 in Tyuratam. Anatoly Filipchenko and Nikolai Rukavishnikov were onboard. It was the first use of the 11A511U rocket variant in a piloted mission.

The ascent to orbit went as planned, and the mission was announced as Soyuz-16, but, again unknown to all those uninvolved at the time, when the cosmonauts opened the hatch from the Descent Module, SA, into the Habitation Module, BO, the "BO depressurization" alarm lit up on the main control console in the cabin. According to official instructions, such a contingency required the crew to immediately close the hatch and seal their safety pressure suits, but Filipchenko reported to the ground that a pressure gauge in the Descent Module showed no sign of air loss. He then ventured into the Habitation Module and confirmed that more accurate indicators inside the compartment had not registered any drop in pressure. The problem was eventually attributed to a sensor error. (231)

The first test objective of the mission, performed around seven hours after launch, was reducing the pressure in the cabin from the usual 720 millimeters of mercury to 540 millimeters, to simulate preparations for configuring the life-support system parameters for opening the hatches into the Apollo spacecraft. (50) However aboard Soyuz-16, the opening of the required valve did not initiate air venting. Mission control quickly established that the experimental ring, simulating the Apollo's docking mechanism, which in stored position was pressed to the opposing docking interface on Soyuz with a pressure reaching 16 tons, prevented air from escaping via an opening in the port. The crew then commanded the ring to retract, which resolved the issue. (231)

Finally, after a 10-hour 40-minute work day, the crew got an eight-hour resting period.

In another surprise for independent observers, the initial orbit of the Soyuz-16 flight, which was tracked by Western radar but not detailed by the Soviet sources at the time, ended up with a considerably higher apogee than the one planned for the Apollo-Soyuz. A Soviet source later cited Soyuz-16 entering the 191.7 by 314.8-kilometer orbit with an inclination 51.79 degrees toward the Equator. (2) Perhaps, it was due to an overperformance of the launch vehicle or it was done to demonstrate the range of orbital maneuvers available to Soyuz. (50)

In any case, on the first and second day of the flight, Soyuz-16 performed three major orbit-correction maneuvers (during Orbit 4, 17, and 18), entering the 225-kilometer orbit agreed upon with NASA for docking with the Apollo.

On the second day of the flight, the crew completed the re-adjustment of the atmospheric pressure, this time, dropping to the targeted 510 millimeters of mercury.

The crew also tested all other new systems intended for the joint mission, first of all the docking mechanism, but also the motion control and life-support system. The testing of the docking mechanism involved multiple retractions and re-engagements of the test ring with the docking port on Soyuz, but the fixating latches on the petals of the port remained closed, keeping the test ring connected to the spacecraft.

The cosmonauts also activated and tried out a brand-new color TV transmission system. They used a red banner, given to them by a young communist organization before launch, as a calibration sample for the camera.

The crew also performed various secondary experiments, including photography of the Earth's surface, and monitoring of biological specimens, such as fish, small plants and microorganisms.

On the fourth day of the flight, the Soyuz-16 crew repressurized its compartments to 830 millimeters of mercury.

Finally, on Dec. 7, 1974, or 119 hours and 20 minutes into the flight and just one day before the scheduled landing, the crew conducted a demonstration of an emergency undocking from Apollo, by firing pyrotechnic bolts holding the test ring and releasing a special spring mechanism that pushed the ring away from the spacecraft. The crew used a movie camera installed on the top hatch of the Habitation Module to document the undocking. "Looks like we fly in the midst of bolts and fasteners," Rukavishnikov said when catching a glimpse of departing ring and its fixation hardware through the window. The ring was reported burning up in the atmosphere the next day.

Four hours later, the crew also adjusted the pressure inside the spacecraft to the operational 760 millimeters of mercury, normally used aboard Soyuz. The operation was accompanied by the unpleasant smell which was traced to a piece of meat which had flown away during one of the meals and been stuck in the air filter to rot for several days. (231)

The cosmonauts also put their biological samples into an alcohol solution for preservation. After the sixth and final sleep period in space, the cosmonauts spent their final four hours in orbit getting back into their safety pressure suits, closing the hatch between the modules and taking seats in the Descent Module. (50)

During the reentry and landing on Dec. 8, 1974, the Soyuz-16 mission tested new ablative material which produced so much soot deposits on the windows that the cosmonauts could not even see the sun, according to their recollections. Nevertheless, the capsule landed successfully at 11:03:35 Moscow Time, 300 kilometers north of Dzhezkazgan in Kazakhstan, meeting all the objectives of the Soyuz-16 mission and formally completing flight testing of the Soyuz 7K-TM variant. (231, 52) Soyuz-16 also came within 10 minutes of the flight duration planned for a joint Soyuz mission with the Apollo.

On Dec. 13, 1974, the cosmonaut training center in Star City held a traditional post-flight press-conference with the Soyuz-16 crew, which was opened to a large group of foreign journalists. Robert White, Head of American Working Group 3 in the Apollo-Soyuz project, who was in Moscow for the joint tests of the Apollo-Soyuz docking system, was also invited, apparently the first NASA official who got that chance. (201, 1044)

Decades later, in an interview marking the 45th anniversary of the Apollo-Soyuz project, Filipchenko said that as many as 20 tests of the docking mechanism during the Soyuz-16 mission gave enough confidence to the Soviet engineers to cancel another piloted test mission ahead of the joint flight. Filipchenko also claimed that, after the Soyuz-16 landing, members of the primary crew for the joint flight — Aleksei Leonov and Valery Kubasov — felt that they could be replaced by the Soyuz-16 veterans due to their experience and stellar performance during the flight. It took his conversation with the head of the Air Force, (who formally oversaw cosmonaut training) to resolve this "misunderstanding," Filipchenko said.

Next page: Soyuz 7K-S

The article by Anatoly Zak; Last update: December 3, 2024

Page editor: Alain Chabot; Last edit: December 3, 2024

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Anatoly Filipchenko (left) and Nikolai Rukovishnikov posing outside the Soyuz simulator at the Cosmonaut Training Center, TsPK. Click to enlarge.

Nikolai Rukavishnikov (foreground) and Anatoly Filipchenko during training inside Soyuz simulator the Cosmonaut Training Center, TsPK. Click to enlarge.

A Soyuz-16 crew during training in the Soyuz 7K-TM simulator.

A Soyuz 7K-TM spacecraft during preparation for launch.

A Soyuz-16 crew boards the spacecraft on Dec. 2, 1974.

Docking ring after its separation from the Soyuz-16 spacecraft as seen by an onboard camera.